This image provided by the Kosciusko County Sheriff's Department shows a chain-reaction crash involving four buses Wednesday in North Webster, Ind. The crash left dozens of middle and high school students with non-serious injuries and one driver seriously injured. (ASSOCIATED PRESS / Kosciusko County Sheriff's Department)

NORTH WEBSTER, Ind. (AP) — A school bus slammed into the back of another one Wednesday afternoon, setting off a chain-reaction crash involving four buses in northern Indiana, leaving about 50 middle and high students with non-serious injuries and one driver seriously injured.

The crash injured 55 people, including three of the four bus drivers, Kosciusko County Sheriff’s Department Sgt. Chad Hill said.

One of the drivers was taken by helicopter to Parkview Hospital in Fort Wayne. A doctor at the scene told school officials the driver’s injuries appeared not to be critical, Hill said.

He said more than 100 students from Wawasee School Corp. were on the buses when the accident occurred about a mile north of North Webster, which is about 40 miles west of Fort Wayne.

The exact cause of the accident that happened about 3:30 p.m. Wednesday likely won’t be released for days because the buses need to be inspected for any mechanical problems, Hill said.

Most of the injured went to Kosciusko Community Hospital in Warsaw, where spokeswoman Joy Lohse said 43 of the patients first to arrive were not in serious or critical condition. Lohse said she didn’t have any additional information, including how many of the patients were students or their exact conditions.

Hill said the number of injured there rose as the evening went on because of walk-ins or students brought in by their parents after first going home.

A nursing supervisor at IU Health Goshen Hospital in Goshen said four students being treated there were in good condition.

Photos from the scene showed the bus in the back of the collision had heavy damage to the front end, with the hood of the vehicle lying in the road. The bus in front of it had a deep dent in the back. The damage to the other two vehicles was not as visible.

Hill said the accident apparently occurred when the bus at the front apparently stopped to let a student off.

Children who were not injured were taken by another bus to Wawasee Middle School where they were picked up by their parents, Hill said.